diff --git a/lib/committee/schema_validator/open_api_3/parameter_deserializer.rb b/lib/committee/schema_validator/open_api_3/parameter_deserializer.rb
index c315dd92..2c3dbc12 100644
--- a/lib/committee/schema_validator/open_api_3/parameter_deserializer.rb
+++ b/lib/committee/schema_validator/open_api_3/parameter_deserializer.rb
@@ -52,6 +52,8 @@ def deserialize_params_by_location(raw_params, location)
           # If no parameters are defined for this location, return raw params as-is
           return raw_params if params_for_location.empty?
 
+          raw_params = normalize_raw_params(raw_params, location, params_for_location)
+
           # Collect parameter names that will be deserialized
           # This includes both the parameter name and any properties (for exploded objects)
           deserialized_keys = Set.new
@@ -105,6 +107,65 @@ def convert_to_indifferent_hash(hash)
           Committee::Utils.indifferent_hash.merge(hash)
         end
 
+        # Normalize Rack-style nested query hashes into bracket notation when the
+        # schema expects bracket-named params or deepObject query params.
+        # Example: { "filter" => { "slug" => "/test" } } => { "filter[slug]" => "/test" }
+        # @param [Hash] raw_params
+        # @param [String] location
+        # @param [Array<OpenAPIParser::Schemas::Parameter>] params_for_location
+        # @return [Hash]
+        def normalize_raw_params(raw_params, location, params_for_location)
+          return raw_params unless location == 'query'
+          return raw_params unless raw_params.values.any? { |value| value.is_a?(Hash) }
+          return raw_params unless requires_query_param_flattening?(params_for_location)
+
+          normalized = Committee::Utils.indifferent_hash
+
+          raw_params.each do |key, value|
+            if should_flatten_query_param?(key, value, params_for_location)
+              flatten_nested_query_param(normalized, key.to_s, value)
+            else
+              normalized[key] = value
+            end
+          end
+
+          normalized
+        end
+
+        # @param [Array<OpenAPIParser::Schemas::Parameter>] params_for_location
+        # @return [Boolean]
+        def requires_query_param_flattening?(params_for_location)
+          params_for_location.any? { |param_def| param_def.style == 'deepObject' || param_def.name.include?('[') }
+        end
+
+        # @param [String, Symbol] key
+        # @param [Object] value
+        # @param [Array<OpenAPIParser::Schemas::Parameter>] params_for_location
+        # @return [Boolean]
+        def should_flatten_query_param?(key, value, params_for_location)
+          return false unless value.is_a?(Hash)
+
+          key_name = key.to_s
+          params_for_location.any? do |param_def|
+            param_def.name == key_name || param_def.name.start_with?("#{key_name}[")
+          end
+        end
+
+        # @param [Hash] result
+        # @param [String] prefix
+        # @param [Object] value
+        # @return [void]
+        def flatten_nested_query_param(result, prefix, value)
+          case value
+          when Hash
+            value.each do |child_key, child_value|
+              flatten_nested_query_param(result, "#{prefix}[#{child_key}]", child_value)
+            end
+          else
+            result[prefix] = value
+          end
+        end
+
         # Extract and deserialize a single parameter
         # @param [OpenAPIParser::Schemas::Parameter] param_def Parameter definition
         # @param [Hash] raw_params Raw parameters
diff --git a/test/middleware/request_validation_open_api_3_test.rb b/test/middleware/request_validation_open_api_3_test.rb
index 43e4aae4..15e98179 100644
--- a/test/middleware/request_validation_open_api_3_test.rb
+++ b/test/middleware/request_validation_open_api_3_test.rb
@@ -660,6 +660,44 @@ def app
     end
   end
 
+  describe 'bracket-style query params' do
+    it 'validates query params declared with bracket notation names' do
+      check_parameter = lambda { |env|
+        assert_equal '/test', env['committee.query_hash']['filter[slug]']
+        refute env['committee.query_hash'].key?('filter')
+        [200, {}, []]
+      }
+
+      @app = new_rack_app_with_lambda(check_parameter, schema: query_param_schema(bracket_notation_query_parameter))
+
+      get '/events?filter[slug]=%2Ftest'
+
+      assert_equal 200, last_response.status
+    end
+
+    it 'rejects unknown nested query params with strict_query_params' do
+      @app = new_rack_app(schema: query_param_schema(bracket_notation_query_parameter), strict_query_params: true)
+
+      get '/events?filter[slug]=%2Ftest&filter[status]=active'
+
+      assert_equal 400, last_response.status
+      assert_match(/filter\[status\]/, last_response.body)
+    end
+
+    it 'continues to support deepObject query params from Rack nested hashes' do
+      check_parameter = lambda { |env|
+        assert_equal '/test', env['committee.query_hash']['filter']['slug']
+        [200, {}, []]
+      }
+
+      @app = new_rack_app_with_lambda(check_parameter, schema: query_param_schema(deep_object_query_parameter))
+
+      get '/events?filter[slug]=%2Ftest'
+
+      assert_equal 200, last_response.status
+    end
+  end
+
   private
 
   def new_rack_app(options = {})
@@ -674,4 +712,53 @@ def new_rack_app_with_lambda(check_lambda, options = {})
       run check_lambda
     }
   end
+
+  def query_param_schema(parameter)
+    Committee::Drivers.load_from_data(query_param_document(parameter), nil, parser_options: { strict_reference_validation: true })
+  end
+
+  def bracket_notation_query_parameter
+    {
+      'name' => 'filter[slug]',
+      'in' => 'query',
+      'required' => true,
+      'schema' => { 'type' => 'string' },
+    }
+  end
+
+  def deep_object_query_parameter
+    {
+      'name' => 'filter',
+      'in' => 'query',
+      'required' => true,
+      'style' => 'deepObject',
+      'explode' => true,
+      'schema' => {
+        'type' => 'object',
+        'required' => ['slug'],
+        'properties' => {
+          'slug' => { 'type' => 'string' },
+        },
+      },
+    }
+  end
+
+  def query_param_document(parameter)
+    {
+      'openapi' => '3.0.3',
+      'info' => { 'title' => 'test', 'version' => '1.0.0' },
+      'paths' => {
+        '/events' => {
+          'get' => {
+            'parameters' => [parameter],
+            'responses' => {
+              '200' => {
+                'description' => 'ok',
+              },
+            },
+          },
+        },
+      },
+    }
+  end
 end